QDPR, CCND1, CAV1, BCL2, BAX, PPDPF, PTEN, C20orf152, ABCB5, ATP2C2, TMEM61, HAO2, MYPN, LRRC39, VHL, and STOM genes have potential as biomarkers for AD diagnosis and prediction of conversion from CN to AD. The gene discussed is PPDPF; the disease is Alzheimer disease.